Medical device insertion and exit information using distributed fiber optic temperature sensing

ABSTRACT

A system, device and method include a sensing enabled device having an optical fiber configured to perform distributed sensing of temperature-induced strain. An interpretation module is configured to receive optical signals from the optical fiber within a body and interpret the optical signals to determine one or more temperature transition points sensed by the sensing enabled device for image registration.

Cross-reference To Prior Applications

This application is a divisional of prior application Ser. No.14/240,032 filed Feb. 21, 2014. Ser. No. 14/240,032 is a U.S. NationalPhase application under 35 U.S.C. § 371 of International ApplicationSerial No. PCT/IB2012/054379, filed on Aug. 27, 2012, which claims thebenefit of U.S. Application Ser. No. 61/530,443, filed on Sep. 2, 2011.These applications are hereby incorporated by reference herein.

This disclosure relates to medical instruments and more particularly toshape sensing optical fibers in medical applications for evaluating anddetermining insertion/exit or other information for medical devices.

Minimally invasive procedures involve making small incisions orkeyholes, for inserting devices to perform a procedure. In manyinstances, it is important to know the point of insertion relative tothe device and patient, for example, to determine the portion of thedevice currently residing within the body versus outside the body. Thedevices inserted are typically elongated and may extend a significantdistance into the body. In addition, the length may change dynamicallyduring a procedure changing how much of the instrument is inside thebody.

In accordance with the present principles, a system, device and methodinclude a sensing enabled device having an optical fiber configured toperform distributed sensing of temperature-induced strain. Aninterpretation module is configured to receive optical signals from theoptical fiber within a body and interpret the optical signals todetermine one or more temperatures or temperature gradients of thedevice.

A workstation includes a medical instrument including a sensing devicehaving at least one optical fiber and configured to perform distributedsensing of temperature-induced strain. A processor is provided, andmemory is coupled to the processor having an interpretation modulestored therein and configured to receive optical signals from the atleast one optical fiber within a subject and interpret the opticalsignals to determine at least one temperature or temperature gradient ofthe device. A display is coupled to the processor and configured todisplay temperature and/or temperature gradient information relative tothe subject.

A method includes collecting strain data from a fiber optic strainsensing device disposed within at least two different temperatureregions; determining a temperature transition point between the at leasttwo different temperature regions based on the strain data and locatingthe transition point relative to a medical device to find a specificreference location.

These and other objects, features and advantages of the presentdisclosure will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings.

This disclosure will present in detail the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a block/flow diagram showing a system and workstation whichemploy a temperature/shape sensing system in accordance with oneembodiment;

FIG. 2 is a graphic image showing a possible display for indicating areference position between two temperature regions in accordance withthe present principles;

FIG. 3 is a diagram of a sensing device with a cross-section depictedshowing multiple optical fibers in accordance with one illustrativeembodiment; and

FIG. 4 is a block/flow diagram showing a system/method for gathering andemploying sensed strain data for determining temperature transitions asreference positions in accordance with another illustrative embodiment.

In accordance with the present principles, a system for determining aninsertion/exit position of a medical instrument and for determining howmuch of an instrument is internal to a patient versus external to thepatient is provided. In accordance with one particularly usefulembodiment, a fiber optic strain sensing device is employed with amedical instrument. Shape sensing based on fiber optics exploits theinherent backscatter in a conventional optical fiber. A principleinvolved makes use of distributed strain measurement in the opticalfiber using characteristic Rayleigh backscatter patterns or otherreflective features. A fiber optic strain sensing device is mounted onor integrated in a medical instrument such that the fiber optic sensingdevice can show a shape as well as a spatially resolved temperaturedistribution for the medical instrument. In one embodiment, temperatureis employed to measure the position of entry/exit of the fiber enableddevice within the body. This information can be employed to calculate alength of the instrument within the body as the device is inserted andmanipulated further within the body in a real-time fashion.

In one example, four or more core fibers may be employed where one coreis located in the center of the cross-section, in such an arrangementone is able to separate strain due to bending from temperature effects(e.g., when axial strain (tension) is not present, or if the tension isknown and controllable (or can be calibrated out)). Combined shape andtemperature sensing may be provided in one embodiment. In otherembodiments, only temperature effects may be measured with as few as oneoptical fiber.

In one illustrative embodiment, a system performs distributed fiberoptic sensing of strain and temperature and is capable of reconstructingthe shape of an elongated medical device, where a spatially resolvedtemperature measurement is used to identify temperature gradients causedby transitions between locations inside and outside the body. The strainmeasurements may be employed to determine the device shape and determinespecific locations along the device using temperature gradients. Thesystem is able to determine the portion of the device residing withindomains of different temperatures, e.g., inside versus outside the humanbody, inside versus outside a thermally treated zone (e.g., an ablationzone), etc.

Furthermore, detection of a fixed insertion point can be used to specifya patient specific reference launch region that moves in a patient'scoordinate frame of reference rather than a lab frame of reference. Foraccurate shape sensing, ambient temperature around the shape sensingdevice is employed to calibrate the device for intra-procedural use,e.g., a shape sensing component operating at room temperature outsidethe body and a second component in-vivo that operates at bodytemperature. Shape sensing accuracy in both segments is necessary andtherefore, segment specific temperature calibration is preferred.

It should be understood that the present invention will be described interms of medical instruments; however, the teachings of the presentinvention are much broader and are applicable to any fiber opticinstruments. In some embodiments, the present principles are employed intracking or analyzing complex biological or mechanical systems (e.g.,plumbing systems or the like). In particular, the present principles areapplicable to internal tracking procedures of biological systems,procedures in all areas of the body such as the lungs, gastro-intestinaltract, excretory organs, blood vessels, etc. The elements depicted inthe FIGS. may be implemented in various combinations of hardware andsoftware and provide functions which may be combined in a single elementor multiple elements.

The functions of the various elements shown in the FIGS. can be providedthrough the use of dedicated hardware as well as hardware capable ofexecuting software in association with appropriate software. Whenprovided by a processor, the functions can be provided by a singlededicated processor, by a single shared processor, or by a plurality ofindividual processors, some of which can be shared. Moreover, explicituse of the term “processor” or “controller” should not be construed torefer exclusively to hardware capable of executing software, and canimplicitly include, without limitation, digital signal processor (“DSP”)hardware, read-only memory (“ROM”) for storing software, random accessmemory (“RAM”), non-volatile storage, etc.

Moreover, all statements herein reciting principles, aspects, andembodiments of the invention, as well as specific examples thereof, areintended to encompass both structural and functional equivalentsthereof. Additionally, it is intended that such equivalents include bothcurrently known equivalents as well as equivalents developed in thefuture (i.e., any elements developed that perform the same function,regardless of structure). Thus, for example, it will be appreciated bythose skilled in the art that the block diagrams presented hereinrepresent conceptual views of illustrative system components and/orcircuitry embodying the principles of the invention. Similarly, it willbe appreciated that any flow charts, flow diagrams and the likerepresent various processes which may be substantially represented incomputer readable storage media and so executed by a computer orprocessor, whether or not such computer or processor is explicitlyshown.

Furthermore, embodiments of the present invention can take the form of acomputer program product accessible from a computer-usable orcomputer-readable storage medium providing program code for use by or inconnection with a computer or any instruction execution system. For thepurposes of this description, a computer-usable or computer readablestorage medium can be any apparatus that may include, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The medium can be an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system (or apparatus or device) or apropagation medium. Examples of a computer-readable medium include asemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), a read-only memory (ROM), arigid magnetic disk and an optical disk. Current examples of opticaldisks include compact disk-read only memory (CD-ROM), compactdisk-read/write (CD-R/W), Blu-Ray™ and DVD.

Referring now to the drawings in which like numerals represent the sameor similar elements and initially to FIG. 1, a system 100 for performinga procedure using temperature sensing enabled devices is illustrativelyshown in accordance with one embodiment. System 100 may be employed withand is applicable for all applications for interventional and surgicalprocedures that employ fiber optic shape sensing. Distributed fiberoptic sensing of strain and temperature may be employed to reconstructthe shape and/or temperature of an elongated medical device 102.Spatially resolved temperature measurement is used to identifytemperature gradients caused by transitions between locations insideand/or outside a body 131. The strain measurements are employed todetermine device shape and determine specific locations along the devicehaving temperature gradients. Portions of the device 102 residing withindomains of different temperatures, e.g., inside versus outside the humanbody or inside versus outside a thermally treated zone, may bedetermined.

System 100 may include a workstation or console 112 from which aprocedure is supervised and/or managed. Workstation 112 preferablyincludes one or more processors 114 and memory 116 for storing programsand applications. Memory 116 may store an optical sensing andinterpretation module 115 configured to interpret optical feedbacksignals from a shape and/or temperature sensing device or system 104.Optical sensing module 115 may be configured to use the optical signalfeedback (and any other feedback, e.g., electromagnetic (EM) tracking,live multimodality imaging data, or other monitoring data availablewithin the clinical environment) to reconstruct deformations,deflections and other changes associated with a medical device orinstrument 102 and/or its surrounding region. The medical device 102 mayinclude a catheter, a guidewire, a probe, an endoscope, a robot, anelectrode, a filter device, a balloon device, or other medicalcomponent, etc. In a particularly useful embodiment, sensing device 104includes a temperature sensing configuration which may be employed withor independently from the medical device 102.

A temperature sensing system includes module 115 and shape/temperaturesensing device 104 mounted on or integrated into the device 102. Thesensing system includes an optical interrogator 108 that providesselected signals and receives optical responses. An optical source 106may be provided as part of the interrogator 108 or as a separate unitfor providing light signals to the sensing device 104. Sensing device104 includes one or more optical fibers 126 which are coupled to thedevice 102 in a set pattern or patterns. The optical fibers 126 connectto the workstation 112 through cabling 127. The cabling 127 may includefiber optics, electrical connections, other instrumentation, etc., asneeded.

Sensing device 104 with fiber optics may be based on fiber optic Bragggrating sensors. A fiber optic Bragg grating (FBG) is a short segment ofoptical fiber that reflects particular wavelengths of light andtransmits all others. This is achieved by adding a periodic variation ofthe refractive index in the fiber core, which generates awavelength-specific dielectric mirror. A fiber Bragg grating cantherefore be used as an inline optical filter to block certainwavelengths, or as a wavelength-specific reflector.

A fundamental principle behind the operation of a fiber Bragg grating isFresnel reflection at each of the interfaces where the refractive indexis changing. For some wavelengths, the reflected light of the variousperiods is in phase so that constructive interference exists forreflection and, consequently, destructive interference for transmission.The Bragg wavelength is sensitive to strain as well as to temperature.This means that Bragg gratings can be used as sensing elements in fiberoptical sensors. In an FBG sensor, the measurand (e.g., temperature orstrain) causes a shift in the Bragg wavelength.

One advantage of this technique is that various sensor elements can bedistributed over the length of a fiber. Incorporating three or morecores with various sensors (gauges) along the length of a fiber that isembedded in a structure permits a three dimensional form of such astructure to be precisely determined, typically with better than 1 mmaccuracy. Along the length of the fiber, at various positions, amultitude of FBG sensors can be located (e.g., three or more fibersensing cores). From the strain measurement of each FBG, the temperatureand the curvature of the structure can be inferred at that position.From the multitude of measured positions, the total three-dimensionalform is determined and temperature differences can be determined.

As an alternative to fiber-optic Bragg gratings, the inherentbackscatter in conventional optical fiber can be exploited. One suchapproach is to use Rayleigh scatter in standard single-modecommunications fiber. Rayleigh scatter occurs as a result of randomfluctuations of the index of refraction in the fiber core. These randomfluctuations can be modeled as a Bragg grating with a random variationof amplitude and phase along the grating length. By using this effect inthree or more cores running within a single length of multi-core fiber,the 3D shape, temperature and dynamics of the surface of interest can befollowed.

An imaging system 110 may be employed for in-situ imaging of a subject131 during a procedure. The imaging system 110 may be incorporated withthe device 102 (e.g., intravenous ultrasound (IVUS), etc.) or may beemployed externally to the subject 131. Imaging system 110 may also beemployed for collecting and processing pre-operative images (e.g., imagevolume 130) to map out a region of interest in the subject to create animage volume for registration and with shape/temperature sensing space.

In one embodiment, workstation 112 includes an image generation module148 configured to receive at least one temperature gradient of thedevice 102 and register an image to the at least one temperaturegradient or otherwise display the results from the sensing device 104.Workstation 112 includes a display 118 for viewing internal images of asubject (patient) 131 and may include an overlay or other image showingan entry/exit point of the device 102 (and/or sensing device 104). FIG.2 shows an illustrative display image. Imaging system 110 may include afluoroscopy system, a computed tomography (CT) system, an ultrasonicsystem, etc. Display 118 may also permit a user to interact with theworkstation 112 and its components and functions, or any other elementwithin the system 100. This is further facilitated by an interface 120which may include a keyboard, mouse, a joystick, a haptic device, or anyother peripheral or control to permit user feedback from and interactionwith the workstation 112.

In another embodiment, system 100 includes a method to compute a pointof entry 140 of the shape/temperature sensing enabled device 102 withinthe body 131 without employing any other imaging or tracking scheme orrelying on any outside technology or user observation/intervention. Thesystem 100 computes the point of entry 140 dynamically in real-time andto know the exact portion of the sensing device 104 entering the body131. For a fiber-optic shape sensing system, detection of the fixedinsertion point 140 can be employed to specify a patient specificreference launch region that moves in the patient's coordinate frame ofreference rather than a frame of reference of the environment (e.g., thelab or operating room). For accurate shape/temperature sensingperformance, the ambient temperature around the optical fiber 126 isneeded as a factor to calibrate the device 104 for intra-procedural use.For example, the ambient room temperature dominates a first portion 142of the sensing device 104 outside the body, and a second portion 144 invivo operates at body temperature. Shape sensing accuracy in bothsegments is needed and therefore, segment specific temperaturecalibration is preferred.

In one embodiment, each of N segments 152 of optical fiber 126 mayinclude a temperature reference component 154 to provide a calibrationtemperature for each respective segment 152. This may be employed duringa procedure or as a calibration step in advance or after the procedure.The optical measurements recorded by the distributed fiber sensor 104can be calibrated into accurate temperature values by use of the knownfiber shapes and tension, in combination with the independenttemperature reference 154, e.g., a thermistor reading, or from exposureof the fiber to known temperatures and temperature changes in acalibration step.

Referring to FIG. 2, a graphic or image 200 showing a possible display(e.g., on display 118) is illustratively depicted. A rendering 202 of apatient may include a generic outline or may include an actual real-timeor pre-recorded image of the patient or portion of the patient. Theimage 200 may include a rendering 206 of the sensing device 104 and mayshow different textures or colors relative to an entry point 208(temperature change). For example, a first portion 242 of the sensingdevice 104 is outside the body 131, and a second portion 244 is insidethe body 131.

The graphic 200 includes a graph 210 that provides a real-time means ofcalculating the length of the shape sensing enabled device 102 that iswithin the body 131, which may be needed for, e.g., endoluminalapplications both diagnostic and therapeutic to perform a biopsy from adesired target lesion, rather than from the wrong region due toovershoot/undershoot of device insertion. In so doing, improvements indiagnostic yield may be realized during interventional procedures. Thegraph 210 shows an external temperature region 212 and an internaltemperature region 216 and a transition temperature region 214. Thetransition temperature region 214 provides a transition into the body131, which is employed to determine the entry point 208. In addition, arunning computation 220 may be displayed showing an inserted length 222and an external length 224. Other graphics and visual tools are alsocontemplated and may be employed.

The temperature of the human body at 37 degrees C. is higher than theambient temperature in an operating room or an interventional suite(around 20 degrees C., e.g., with air conditioning, etc.). As a result,at the point when the fiber device enters into the body, the fiber willundergo a gradient or gradual change in temperature from 20 to 37degrees C. (assuming normal human body temperature). This position canbe dynamically detected during advancement of the device 104. Thermalcapacities introduced by the material surrounding the fiber, however,may lead to larger time constants affecting the response time of thesystem to temperature changes. These may be accounted for in the designor in the computation, for example.

In an alternate embodiment, shape/temperature sensing data may bematched to imaging data, both pre-operative and intra-operative, as longas the point of entry 208 is visible in the imaging space. For example,an image of the body 131 and a rendering of the sensing device 104 maybe displayed together. The entry point 208 may provide a commonreference to register both spaces. This addresses the problems faced inregistration when either the fiber 126 itself is not visible in thefield of view, or if the fiber segment 152 that is present lackssufficient structural detail to allow for unambiguous fusion (e.g., thefiber device appears as a single line extending through the field ofview).

Referring to FIG. 3, a shape/temperature sensing device 104 isillustratively shown with a cross-sectional view. An optical fiber maybe employed to measure strain and is also sensitive to temperature. Inone embodiment, three outer fiber cores 302 are disposed about a fourthcentral core 304. With this combination, separate measurements of strainmay be obtained leading to shape (cores 302) and spatially resolvedtemperature (along the length) (core 304). The configuration works bestif there is no axial strain present. In most scenarios, axial strain ofthe device 104 is negligible since the device is not stretched along itslength, and therefore it is reasonable to assume that the primaryinfluence in the central core 304 is due to temperature. Otherconfigurations may also be employed to zero out or account for axialstrain if present. For example, a second central core (not shown) withdifferent properties from the first core may be provided such thatphysical strain and temperature strain may be distinguished. The secondcentral core may be provided with different properties or differentdoping material to give a different refractive index and/or coefficientof expansion. These same features or differences can also be applied tothe outer cores (not just central the central core or cores) where eachcore could have a different property such that measurement differenceswould permit multiple solutions to resolve axial strain, temperaturevalues, etc.

Changes in temperature along the length of the device 104 are monitoredto dynamically determine the insertion point (208) or more generallydetermine positions within different temperature domains. As mentioned,this can be combined with pre-operative imaging to predict whether atarget is being approached. It can also be used to match and registerthe pre-operative imaging to the shape sensing system when the point ofentry is also visible in the imaging modality.

With the configuration of four cores (302, 304), strains fromtemperature can be easily distinguished from geometrical strains. Thestrains in cores 302 may be employed to resolve temperature regionsalong the fibers as the geometry indicated by the cores 302 will providepositional information relative to the information collected from thecentral core 304. In addition, the fiber optic sensor 104 may provideadditional optical measurements, such as backscatter, etc., which can beused to more accurately solve ill-posed estimation problems by teasingapart temperature from deformation-induced changes in the opticalbackscatter.

It should be understood however that a single fiber core may be employedas a temperature sensor. This is particularly useful where other strainsin the single fiber are known. In fiber configurations with even morecores (e.g., say, up to 7 cores), the cores are preferably evenly orsymmetrically distributed about the central core. In one example, sevencores may be employed with 6 exterior cores in a hexagonal form and onecore in the center. Other configurations are also contemplated.

A physical length and index of refraction of a fiber are intrinsicallysensitive to environmental parameters of temperature and strain and, toa much lesser extent, pressure, humidity, electromagnetic fields,chemical exposure etc. The wavelength shift, Δλ or frequency shift, Δνof the backscatter pattern due to a temperature change, ΔT, or strainalong the fiber axis, ε, is: Δλ/λ=−Δν/ν=K_(T)ΔT+K_(ε) where

$K_{g} = {1 - {\frac{n_{eff}^{2}}{2}{( {p_{12} - {\mu ( {p_{11} + p_{12}} )}} ).}}}$

The temperature coefficient K_(T) is a sum of the thermal expansioncoefficient α and the thermo-optic coefficient ξ=1/n(∂n/∂T), withtypical values of 0.55×10−6° C.⁻¹ and 6.1×10−6° C.⁻¹, respectively forgermanium-doped silica core fibers. The strain coefficient K_(ε) is afunction of group index n (or n_(eff)); the components of thestrain-optic tensor, p_(ij) and Poisson's ratio, μ. Usual values givenfor n, p₁₂, p₁₁ and μ for germanium-doped silica yield a value for Kε ofabout 0.787. Thus, a shift in temperature or strain may be a linearscaling (for moderate temperature and strain ranges) of the spectralfrequency shift Δν. This linear model does not apply if strains approachthe elastic limit of the fiber, or temperatures approach the glasstransition temperature of the fiber.

The use of temperature changes detected along the fiber length permitspiecewise constant temperature calibration and segment specific shapereconstruction to be applied to each domain of the fiber sensor (104).This ensures shape tracking accuracy in each region despite the presenceof a temperature gradient at the insertion point (which might normallydegrade the performance of shape sensing/localization).

Other applications of the present principles may include pulmonology orother endoluminal and endovascular applications where a position of atarget, such as a lesion is known in pre-operative computed tomography(CT) images. Knowing this, the path that a pulmonologist has to traverseto reach the target and the length of the path are also known. Inaccordance with the present principles, the clinician also knows thelength of the device that has been moved within the body, and thiscoupled with 3D shape information from the device would be significantin improving the yield of the procedure. The examples described shouldnot be construed as limiting. Other endoluminal procedures that couldbenefit from the present principles include applications ingastroenterology, colorectal procedures, gynecology, urology, etc. Thesensing device 104 may be incorporated in one or more of the followingdevices: cystoscopes, ureteroscopes, rhinolaryngoscopes, gastroscopes,colonoscopes, esophagoscopes, etc.

Referring to FIG. 4, a method for determining a temperature transitionpoint for deciphering a reference location is illustratively shown inaccordance with one embodiment. In block 402, strain data is collectedfrom a fiber optic strain sensing device disposed within at least twodifferent temperature regions. The sensing device may include a firstportion having a first temperature and a second portion having a secondtemperature, and the first portion is internal to a body, and the secondportion is external to the body. In this instance, the transition pointincludes a point of entry in the body. In another example, the firstportion may include a temperature treated zone (ablation zone, cryogenictreated zone, etc.), and the second portion includes a referencetemperature zone. The transition point(s) may be employed to determinean entry/exit point to the body, determine a distance in the body to atarget, determine an ablation region, etc.

The strain data may include geometrical data for determining a shape ofa medical device as well as temperature transitions. In block 404, thesensing data may include temperature induced strain and geometricallyinduced strain. The sensing device may include at least four opticalfibers configured with three optical fibers surrounding a centraloptical fiber such that the three optical fibers measure geometricstrain and the central optical fiber measures a temperature inducedstrain. Other configurations are also contemplated.

In block 406, a temperature transition point is determined between theat least two different temperature regions based on the strain data. Anynumber of regions may be employed. In block 408, the transition point islocated relative to a body and/or a medical device to find a specificreference location. In block 410, locating the transition point mayinclude determining a length of the first portion and a length of thesecond portion.

In block 412, an image of the body may be registered totemperature/shape sensing space using the temperature transition pointas a reference. In block 414, temperature information is displayed. Thetransition point and/or the temperature gradient may be displayed for aclinician to improve accuracy, yield, etc. of a procedure.

In interpreting the appended claims, it should be understood that:

-   -   a) the word “comprising” does not exclude the presence of other        elements or acts than those listed in a given claim;    -   b) the word “a” or “an” preceding an element does not exclude        the presence of a plurality of such elements;    -   c) any reference signs in the claims do not limit their scope;    -   d) several “means” may be represented by the same item or        hardware or software implemented structure or function; and    -   e) no specific sequence of acts is intended to be required        unless specifically indicated.

Having described preferred embodiments for medical device insertion andexit information using distributed fiber optic temperature sensing(which are intended to be illustrative and not limiting), it is notedthat modifications and variations can be made by persons skilled in theart in light of the above teachings. It is therefore to be understoodthat changes may be made in the particular embodiments of the disclosuredisclosed which are within the scope of the embodiments disclosed hereinas outlined by the appended claims. Having thus described the detailsand particularity required by the patent laws, what is claimed anddesired protected by Letters Patent is set forth in the appended claims.

1-28. (canceled)
 29. A method, comprising: collecting strain data from afiber optic strain sensing device disposed within at least two differenttemperature regions, at least one of the regions being internal to abody; determining a temperature transition point between the at leasttwo different temperature regions based on the strain data; locating thetransition point relative to a medical device to find a specificreference location; and registering the fiber optic strain sensingdevice to an image of the body using the temperature transition point asa reference.
 30. The method of claim 29, wherein the sensing deviceincludes a first portion having a first temperature and a second portionhaving a second temperature, and wherein the determining includesdetermining a length of the first portion and a length of the secondportion.
 31. The method of claim 29, wherein the sensing device includesa first portion having a first temperature and a second portion having asecond temperature, and wherein the first portion includes a temperaturetreated zone and the second portion includes a reference temperaturezone.
 32. The method of claim 29 wherein strain data is collected fromthree or more temperature regions.
 33. The method recited in claim 29,wherein the at least two different temperature regions are internal tothe body.
 34. The method of claim 29 wherein the temperature transitionpoint is the only reference used to register the fiber optic strainsensing device to the image of the body.
 35. A system, comprising: asensing enabled device having at least one optical fiber configured toperform distributed sensing of temperature-induced strain; and aninterpretation module configured to receive optical signals from the atleast one optical fiber comprising strain data from within a body andinterpret the optical signals to determine a temperature transitionpoint between at least two different temperature regions based on thestrain data; the system being configured to register the fiber opticstrain sensing device to an image of the body using the temperaturetransition point as a reference.
 36. The system of claim 35, wherein theat least one optical fiber of the sensing enabled device includes afirst portion having a first temperature and a second portion having asecond temperature, and wherein the interpretation module determines thetemperature transition point by using a length of the first portion anda length of the second portion.
 37. The system of claim 35, wherein thesensing enabled device includes a first portion having a firsttemperature and a second portion having a second temperature, andwherein the first portion includes a temperature treated zone and thesecond portion includes a reference temperature zone.
 38. The system ofclaim 35 wherein strain data is collected from three or more temperatureregions.
 39. The system of claim 35, wherein the at least two differenttemperature regions are internal to the body.
 40. The system of claim 35wherein the temperature transition point is the only reference used toregister the fiber optic strain sensing device to the image of the body.41. A workstation, comprising: a medical instrument including a sensingdevice having at least one optical fiber and configured to performdistributed sensing of temperature-induced strain and shape sensing ofthe medical instrument; a processor; memory coupled to the processor andhaving an interpretation module stored therein and configured to receiveoptical signals comprising strain data from the at least one opticalfiber within a subject and interpret the optical signals to determine atemperature transition point between at least two different temperatureregions based on the strain data; and a display coupled to the processorand configured to display internal images of the subj ect.
 42. Theworkstation of claim 41, comprising an image generation moduleconfigured to receive the temperature transition point and register animage to the temperature transition point.
 43. The workstation of claim41, wherein the sensing device includes three or more segments formeasuring temperature.
 44. The workstation of claim 41, comprising atemperature reference component configured to independently calibrate atemperature for at least one segment of the at least one optical fiber.